Back in 2012, [Matt Parker] and a team built a computer out of dominos for the Manchester Science Festival. [Andrew Taylor], part of the team that built the original, has built a series of virtual domino puzzles to help explain how the computer worked. He also links to a video from the event, but be warned: the video contains some spoilers for the puzzles. If you are ready for spoilers, you can watch the video below.

The original computer could add two three-bit numbers and provide a four-bit result. We don’t want to give away the answers, but the inverter is quite strange. If you don’t want to puzzle it out, you can press the “reveal answer” to see [Andrew’s] solutions. Press “play” and watch the dominos fall.

Of course, building an adder is a far cry from building a computer, but at 10,000 dominos, a real computer would be difficult, though clearly possible. This is especially true when you consider that these logic gates can only run once, so testing is a bear. The fact that knocking over a domino takes it out of play is exactly how many of the gates work, too, but that’s the only hint we’ll give.

We couldn’t help but think of the Three Body Problem’s human computer. If you prefer your domino logic to be non-interactive, we’ve covered another presentation on the topic.

https://www.youtube.com/embed/OpLU__bhu2w?feature=oembed